      program demo_expand
      !  test filter to expand escape sequences in input lines
      use M_strings, only : expand
      character(len=1024) :: line
      integer             :: ios
         READFILE: block
            do
               read(*,'(A)',iostat=ios)line
               if(ios /= 0) exit READFILE
               write(*,'(a)')trim(expand(line))
            enddo
         endblock READFILE
      end program demo_expand
